Core Aerate your lawn in the spring.

Helps fertilizer and moisture (when ever we will get more)to get to the roots faster and soak in.

Also apply Gypsum pellets to your lawn if your on a Clay type soil. It helps break up the density and helps the plants/grass get more nutrients out of the existing soil.
Typical 10K SF residential yard, 4 bags or 150lbs. Results are not immediate, but after the first year, it starts to show.

What about sandy soil? I have about 8 inches of black dirt and the rest is sand. We had about a 1/2 inch of rain last night and in 2 days it will be dry and hard.

Coring and Gypsum should provide same results as far as treating the top soil. If applied in spring and fall for a couple seasons, it will condition the black dirt to some extent. The coring will also break up top layer of soil and put the plugs on the top to aid in thatch decomposition.

As far as the drying out part...with the sand under neath, there is no "fix" for that. You will have to treat the 8" of soil and then probably install irrigation system if you want to keep your lawn thick and lush.

Want the best quality turf in the neighborhood?
-Irrigation is key
-Aereate 3-4 times a year(16 cores per sq. foot)
-1.5" of water/rain a week
-fertilize (after soil test) every 40 days
-mow your grass at 3.0" and keep your blades sharpened

REMEMBER:Grass is grown by the inch and killed by the foot!

shannonboen at yahoo.com

Here's a tip! Don't plant the day before hail!

If I may offer an observation on my own behalf:
When I set my, "ts ts ts ts ttststststststs" sprinkler, (know what I mean?) I often move the upper blade and turn the side screw in so that the water comes out at a lower level and a shorter distance. The length of my grass, (as the sprinkler has a low profile), actually disrupts the flow of the projecting water and waters in a smaller area; creating a more watered area near the sprinkler. I do it on purpose because I spot water fairly often. How's the length of your grass?
Just my 1.186 cents